1. Field of the Invention
The present invention relates to an image processing apparatus, a program, a recording medium, and a data decompression method.
2. Description of the Related Art
In recent years, the demand for obtaining an image with extreme fineness is growing due to the advances in image input technology and image output technology. As an example of an image input apparatus, in the area of digital cameras, a high performance CCD (Charge Coupled Device) providing 300 million or more pixels is employed for products sold in a common price range due to the accelerated decrease in the cost of the CCD. Furthermore, the number of pixels is expected to continue increasing.
In the area of image output apparatuses/image display apparatuses including, for example, products that provide hard copies such as laser printers, inkjet printers, and sublimation printers, and products that provide soft copies such as CRT (Cathode Ray Tube) and flat panel displays such as LCD (Liquid Crystal Display) or PDP (Plasma Display Panel), the increase in the fineness of images and the decrease in the cost of products are remarkable.
Due to the advent of high performance/low cost image input/output apparatuses in the market, the use of images of extreme fineness are spreading among the general public, and the demand for images of extreme fineness is expected to increase further in other areas. The advance in network related technologies such as the Internet and the personal computer is the cause for accelerating this trend. Particularly, the rapid growth in the use of mobile devices such as mobile phones and lap top computers allows high quality images to be transmitted and/or received at any given location.
Under these circumstances, image compression/decompression technology, being employed for simplifying the handling of high quality images, is expected to provide higher performance and more functions in the future.
In recent years, a new image compression format referred to as JPEG 2000, which can decompress high quality images compressed at high compression rates, is being standardized for satisfying such expectations. With the JPEG 2000, compression and decompression can be performed in a small memory environment that employs a process of dividing an image into rectangular areas (tiles). That is, each of the tiles serves as a basic unit for performing compression and decompression, to thereby allow the compression/decompression process to be performed on each tile independently. Furthermore, with the JPEG 2000, an image file can be divided into a low resolution data and a high resolution data.
An example of a method of using image files compressed with the JPEG 2000 format is described below. For example, image files compressed with the JPEG 2000 format may be stored in a server computer for allowing a client computer to access the server computer and extract only low resolution data from one of the image files for processing the low resolution data as a thumbnail display. By using this method, network traffic during transmittal from the server computer to the client computer can be reduced and the time for performing the thumbnail display process can be shortened.
However, computers installed with an application capable of decompressing JPEG 2000 compressed image files are limited. That is, there is a problem that a client computer, having no JPEG 2000 decompression function, is unable to perform an image display process even where accessible to a server computer having JPEG 2000 compressed image files stored therein.
Furthermore, although uncompressed image files could be transmitted to the client computer having no JPEG 2000 decompression function, such transmittal of uncompressed image files will increase the amount of network traffic.